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Topic: tupperware holding leachable residues?  (Read 3743 times)

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Offline Invincible

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tupperware holding leachable residues?
« on: December 30, 2009, 05:09:23 PM »
Here's how it got me curious.  I think people know that tupperwares can become permanently stained.  I thought it was purely cosmetic, but it wasn't.  

There was a disposable polypropylene bowl that microwaveable pasta dish came in.  This one was pesto sauce based.  This one came out very clean. During its next wash, it was washed in an automatic dishwasher.  The automatic dishwasher also held utensils and plates used with marinara sauce.  

When the cycle was done, the polypropylene bowl had been dyed red-orange from being washed in waster that contained lycopene.  It looked dyed, but it was clean. Despite this it was followed by detergent+handwash again and surface showed no oil streaks. 


A small amount of trichloroethylene was added to the bowl and the solvent immediately turned orange making it obvious that contaminants can leach out from plastic tupperware like tableware.


The solvent was absorbed onto paper towel and tomato odor was evident in residue after evaporation of TCE.

Though HDPE and PP are said to very inert to contents, it would seem like once used, cross contamination is inevitable.  

I'm thinking that I can weigh a glass beaker to the nearest 0.1mg, wash the supposedly clean plasticware with trichloroethylene and evaporate it in beaker to quantify how much was bled out.  

Does this sound like a plan for a basic analysis of leechable contaminants in plastic containers?  

Offline Grundalizer

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Re: tupperware holding leachable residues?
« Reply #1 on: December 31, 2009, 09:40:38 PM »
Sounds good..or a mass spec would do the trick

Offline marquis

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Re: tupperware holding leachable residues?
« Reply #2 on: December 31, 2009, 09:43:34 PM »
Your approach sounds ok.  When extracting plastics, I used some polar and nonpolar solvents.  Typically, it was acetone, isooctane, and chloroform. TCE would be a good replacement for chloroform.

There are a couple of references that might help.  The United States Pharmacopeia (USP) has a section for plastic.  I believe it is section <661>.   There is another section-section <88> that might fit.  It gives an extraction techniques, although the extract is typically used to dose animals to evaluate toxicity (acute systemic and intracutaneous toxicity).  Plastics are one of the materials that extraction conditions are listed for, usually with relatively high surface area to volume ratios.  You sometimes see plastics advertised as passing these specifications- i.e. class V plastic. Some of the solvents used would not evaporate readily, although they would be applicable to other analytical techniques.

Even a plastic like polyethylene can have many ingredients, some of which will extract.

Good luck with your project.

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